1. Field of the Invention
The present invention relates to a reception antenna intended for picking up signals from a geostationary satellite.
The invention finds an especially advantageous application in the field of the transmission of television signals, be they intended for individual or communal use.
Developments in digital technology have spurred a veritable revolution in the audiovisual sector. Apart from unequaled restitution of picture and sound, digital satellite broadcasting affords genuine interactivity as well as very great flexibility of use so as to be able to accommodate everybody's taste and pace of life.
2. Description of the Related Art
Additionally, an increasingly large number of geostationary satellites are operational for broadcasting ever more numerous and diversified programs. With these comes a generalization towards broadcasting systems using several co-positioned satellites, that is to say which transmit from a single point in the sky. This is in particular the case with the system developed by ASTRA which, like its counterparts, has the advantage of requiring only very simple reception hardware to access a very large number of existing or future programs, namely a single fixed directional antenna.
Schematically, the latter is composed of a reflector, a source and a frequency converter. To make it sufficiently directional, the reflector has the shape of a paraboloid or a portion of a paraboloid. The signals received from the satellite are thus reflected and concentrated at a focal point. The source, an accessory intended for guiding the waves towards the converter which modifies their frequency, is positioned at precisely this location.
The reception antennas used are essentially of the offset type by virtue of their great compactness. On account of its off-centering, the source of this family of parabolas does not in fact cast any shadow on the surface which reflects the signal, thereby affording better gain and consequently making it possible to reduce the dimensions of the antenna.
However, the growing success of this digital technology within the mass market is manifested by a proliferation of parabolic antennas on the facades or roofs of individual houses or communal premises. From around 50 to 80 cm in diameter, they are often deemed to be especially unesthetic and sometimes too bulky when room is tight, as on a window ledge for example.
Moreover, their installation requires the use of a specific support structure and, of course, certain more or less complex adjustment operations so as to accurately position the parabola in the horizontal and vertical planes, as a function of the azimuth and elevation of the targeted satellite.
On account of their design, these reception antennas are also directly exposed to the natural elements such as the sun, the wind, moisture or snow, all factors which are prejudicial to their proper operation.
Additionally, the technical problem to be solved by the subject of the present invention is to propose a reception antenna intended for picking up signals from a geostationary satellite, comprising in particular a paraboloid-shaped reflector able to reflect the signals received and to concentrate them at a focal point whereat is arranged a source able to guide said signals towards a frequency converter, which reception antenna would make it possible to avoid the problems of the prior art while being almost insensitive to meteorological conditions and very easy to install, and yet offering a more discreet appearance.